45 ACP

The .45 ACP (Automatic Colt Pistol), or .45 Auto (11.43×23mm) is a handgun cartridge designed by John Browning in 1905, for use in his prototype Colt semi-automatic pistol. The .45 ACP, is similar in performance to the .45 Schofield cartridge, and significantly shorter than the .45 Colt.